The present invention relates to a mobile communication system, and is particularly adapted to indoor radio telephones in building premises connected to exchanges and in urban areas, and more particularly to mobile switching without interrupting the call even though a service area of a base station has changed during that call.
Conventional similar apparatus of this type have been used in urban mobile telephone systems, as discussed in "Bell System Technical Journal", Vol. 58, No 1, (1979), pp. 43-95. When it is necessary to switch a mobile channel as a mobile unit is moved from the service area of one base station through which a call is being made to the service area of another adjacent base station, a central intelligence decides not only the necessity but also the adjacent base station and thereafter instructs the adjacent base station to prepare a vacant radio channel (hereinafter shortened to CH). Further, the central intelligence alters the registration of the mobile unit and simultaneously switches the CH over to the adjacent base station.